Re: [thredds] THREDDS Garbage Collection Tuning

There are some sites that suggest to cut down on garbage collection set -Xmx 
and --Xms to the same values.  That is what we have been using for awhile and 
it seems to keep things relatively stable.  Plus giving it as much memory as 
possible,

-Roy

On Jun 1, 2011, at 8:57 AM, Rich Signell wrote:

> Ethan,
> 
> According this this article:
> http://www.petefreitag.com/item/746.cfm
> it says
> 
> the "OutOfMemoryError - GC overhead limit exceeded" exception is
> thrown by the garbage collector when it is spending way too much time
> collecting garbage. This error essentially means that you need to add
> more memory, or reconfigure your garbage collection arguments.
> 
> So it seems like the same issue.    Our settings are:
> export JAVA_OPTS="-XX:MaxPermSize=256M -Xmx2048m -Xms512m -server
> -Djava.awt.headless=true"
> 
> -Rich
> 
> On Wed, Jun 1, 2011 at 11:47 AM, Ethan Davis <edavis@xxxxxxxxxxxxxxxx> wrote:
>> Hi Rich,
>> 
>> We haven't ever really fiddled with GC parameters, instead we leave the
>> whole GC settings up to the "-server" JVM.
>> 
>> We've never seen this error on our servers. It doesn't look like your
>> error message is related to the "OutOfMemoryError: PermGen space" issue
>> so I'm not sure "-XX:MaxPermSize" will help.
>> 
>> Have you tried adding more memory to the heap ("-Xmx")? And if so did it
>> help?
>> 
>> Ethan
>> 
>> 
>> On 6/1/2011 9:24 AM, Rich Signell wrote:
>>> THREDDS folk,
>>> 
>>> Have folks played around with Garbage Collection tuning parameters
>>> besides "-XX:MaxPermSize" to help tomcat/TDS permgen errors?
>>> 
>>> Our TDS tomcat is throwing "GC overhead limit exceeded" errors again.
>>> I know on the Unidata TDS page
>>> http://www.unidata.ucar.edu/projects/THREDDS/tech/tds4.2/tutorial/BasicTomcatAndTDSSecurity.html
>>> it says the only thing you can do is increase -XX:MaxPermSize, which
>>> only delays the problem, solved only by restarting tomcat.
>>> 
>>> But in this Garbage Collection tuning article
>>> http://www.petefreitag.com/articles/gctuning/
>>> they describe many different options, and I'm wondering whether folks
>>> have tried using these, or whether they just don't do any good.
>>> 
>>> Thanks,
>>> Rich
>> 
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> 
> 
> 
> -- 
> Dr. Richard P. Signell   (508) 457-2229
> USGS, 384 Woods Hole Rd.
> Woods Hole, MA 02543-1598
> 
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**********************
"The contents of this message do not reflect any position of the U.S. 
Government or NOAA."
**********************
Roy Mendelssohn
Supervisory Operations Research Analyst
NOAA/NMFS
Environmental Research Division
Southwest Fisheries Science Center
1352 Lighthouse Avenue
Pacific Grove, CA 93950-2097

e-mail: Roy.Mendelssohn@xxxxxxxx (Note new e-mail address)
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